Derek Yu originally released the freeware version of underground explorer Spelunky back in 2008, and continued to build on it over the course of 2009, as it gathered press and a sizable fan base.

As Yu finished up on the freeware version, he revealed that a brand new version for Xbox Live Arcade was on the way. The transition from PC to Xbox has taken another two years since then, and Spelunky fans are now eagerly waiting on a release date.

In the meantime, the game has continued to impress, picking up nominations for a total of three awards at the upcoming Independent Games Festival, including the Seumas McNally Grand Prize.

As part of Gamasutra's Road to the IGF series, Yu discusses how the XBLA version of the game came about, and the changes that have occurred since the freeware version.

What is your background in making games?

I started out as a kid in the Klik n' Play community, which, in a lot of ways, felt like a microcosm of the current indie scene. We had our own little team-ups, falling outs, hits, flops, drama... it was lots of fun! And it was a great place to hone your skills in creating games, especially if you're someone who enjoys all aspects of development.

Anyway, most of my games have been freeware. It wasn't until Alec Holowka and I released Aquaria that I put out a commercial title. It's been successful enough to let us both pursue game-making full time, which is really great!

What development tools are you using to develop Spelunky?

Mostly Visual Studio and Photoshop. The original Spelunky was created in Game Maker.

How did you come up with the concept?

After Aquaria came out, I was making some prototypes for simple platformers and roguelikes. The level generation algorithm that I ended up using for Spelunky was actually based on one of those roguelike prototypes... it wasn't too hard to make the connection, I guess! I was also interested in destructible terrain, at the time, and that turned out to be an important part of Spelunky, as well.

Platforming, the simple random level generation system, destructible terrain... once I put all of those together, it wasn't hard to come up with the rest.

How long have you been working on the game?

I've spent about two years on both versions of the game, so four total. The two years on the Xbox 360 version have definitely been more full-time, though.

At what point did you decide that you wanted to take the game past the freeware version and explore it further?

It wasn't until Jonathan Blow came to me and offered to put me in touch with Microsoft that I seriously considered exploring the concept further. I wasn't expecting that the game would become as popular as it did - I was just looking for something fun to do after Aquaria!

But since I respect Jon a lot and he liked it... and since the game was gaining a pretty strong following on the internet... well, it made a lot of sense to pursue such a cool opportunity. And once I started thinking about it seriously new ideas started rolling in. There were a lot of great ideas being passed around by fans, too.

When switching to work on a console version of the concept, were there any specific areas that you had to watch in particular that were more difficult to transition over?

Not really! Platform games have been pretty well-explored on consoles and the more unique aspects of Spelunky (like the random level generation) are platform-independent, for the most part. It's been a pretty smooth transition so far.

Are there any elements that you've experimented with that just flat out haven't worked with your vision?

I implemented an Endless Mode where, instead of going from one level to the next, you make your way down an endless shaft that gets more and more difficult as you go on. As the name implies, it went on forever (or at least until it got too difficult for all but the most superhuman players). I took it out because it didn't really add enough to the basic game (called Adventure Mode in Spelunky XBLA). It was just a novelty when compared to Deathmatch, which is a genuinely new and interesting way to play Spelunky.

If you could start the project over again, what would you do differently?

There's not too much I'd do differently. It's been a challenging development with a lot of surprises, but they've mostly been positive ones. If anything, Spelunky has made me take freeware more seriously for my future plans. It's such a great way to get your ideas out and see what sticks before you go into the pressure cooker that is commercial game-making.

To put it in perspective, Spelunky freeware caught the attention of Jonathan Blow and Microsoft, as well as my two teammates, Andy Hull and Eirik Suhrke. It has its own wiki and mods that were put together by awesome fans. It's served as a great template for the XBLA title. It's all I could ask for from any game I release, and if you asked me whether its development was hard, I'd say no - it was very low stress.

I'm not expecting or wanting every freeware game I make to turn into something bigger, but it's good to know that hobbyist development and commercial development can go hand-in-hand.

Have you played any of the other IGF finalists? Any games you particularly enjoyed?

Yeah, I've played quite a few of them... Johann Sebastian Joust, Wonderputt, Atom Zombie Smasher, English Country Tune, Realm of the Mad God, Gunpoint, Faraway, and GIRP. I've enjoyed them all, but I'm particularly fond of Faraway, which I've played the most. It reminds me of Tetris in some ways - very simple to play but hard to master, with a unique, elegant design that makes so much sense once you see it (but not before).

Overall, I'm really happy with the finalists in the competition this year, and proud to be among them. A lot of games I liked didn't make it, like Infested Planet, The Iconoclasts, and Puzzlejuice, but what can you do? I think those games will do quite well, regardless.

What do you think of the current state of the indie scene?

I like where it's at! I've always hoped that the indie scene would get a good mix of games and game developers, from someone's first game made at a jam to small, quirky one-offs to people's dream projects that will take their entire lives to complete to really polished commercial titles made by small teams of dedicated professionals. That seems like where things are headed, so that's cool!

Some not so cool aspects of the indie scene: people trying to use their "indieness" to excuse poor behavior or do pity marketing. Making games as a small team imposes a lot of real risks and challenges that should be shared, but it's not a license to throw tantrums or manipulate people's emotions to get them to buy your game. To clarify, I think it's perfectly okay to use Kickstarter or ask for donations to fund your development... so long as you're talking about how awesome your game is instead of trying to win pity votes.

Also, there will probably always be a contentiousness over the word "indie" and what it means, what its value is, etc., and even though it can be tiresome to discuss at times, I think it's mostly healthy. So long as people continue to put out their very best work, it doesn't really matter whether you're indie or not. For me it's just a convenient label that represents a lot of what I'm interested in: independence and the capabilities of small, flexible teams with strong personal visions.